The protein hormone secreted by the thyroid gland

Thyrocalcitonin (TCT) is the protein/peptide hormone secreted by the parafollicular cells of the thyroid gland. It regulates the blood calcium levels. It is a hypocalcemic hormone (reduces the blood calcium levels). PTH is the hypercalcemic hormone which increases bone resorption. The follicular cells of the thyroid glands secrete thyroid hormones which bind to intracellular receptors and increase basal metabolic rate. Protein/peptide hormones bind to membrane-bound receptors.